body,html{
    width: 100%;
    height: 100%;
    /* 隐藏滚动条 */
    overflow: hidden;
    padding: 0;
    margin: 0;
    /* 如果页面宽度大于最大宽度就不再延伸 */
    max-width: 600px;
}

body{
    padding: 10px;
    /* 所有动画行为持续1s */
    transition: all 1s;
}
div.pic img{
    width:100%
}
/* 按钮 */
#modeBtn{
    border:0;
    background: transparent;
    font-size: 36px;
    float: right;
    /* 光标的类型变成小手 */
    cursor: pointer;
}
#modeBtn::after{
    content: '🌞';
}
#checkbox{
    display: none;
}
.content{
    width: 100%;
    height: 100%;
    padding: 10px;
    transition: all 1s;
}

#checkbox:checked+ .content #modeBtn::after{
    content: '🌜'
}
#checkbox:checked +.content{
    background: black;
    color: white;
}
body.night {
    background: black;
    color:white;
}
